How to understand the flow and characteristics of the regulating valve

Whether the flow characteristics of the valve is appropriate is directly related to the quality of the valve. The flow characteristics of the valve core should be selected according to the characteristics of the process object. The flow characteristic of the regulating valve is the relationship between the relative flow rate of the regulated medium flowing through the valve and the relative opening of the valve. According to the shape of the spool, it is mainly divided into three types: straight line, equal percentage and quick opening. Under normal circumstances, because the equal percentage flow characteristics of the regulating valve can adapt to the occasion of large load changes, it is often preferred to choose.

In view of the characteristics of the adjustment object, it is extremely important to improve the characteristics of the entire system in consideration of the matching of the flow characteristics of the regulating valve with the object. Object load changes, piping conditions, and adjustment quality should be considered. For example, when controlling a hot water heater or when the pipe resistance is large or the system load changes greatly, the percentage flow characteristics should be selected. If the steam heater or the valve is controlled to have a constant pressure difference or a small change in load, the linear flow characteristic should be selected.